An integrated circuit with some circuits or components in dielectrically isolated silicon may be formed on a silicon-on-insulator (SOI) wafer. SOI wafers are more expensive than bulk and epitaxial wafers, undesirably increasing the cost of the integrated circuit. Alternately, the circuits or components may be formed over buried layers of silicon dioxide; methods to form the buried silicon dioxide layers such as implanting oxygen have been problematic with respect to providing desired lateral and vertical dimension control of the buried oxide layer, and undesirably increase stress on the wafer, leading to problems during photolithographic operations. Forming thin layers of device quality silicon over buried oxide layers has also been problematic.